Endoscopes are widely used in medical procedures, particularly in minimally invasive surgical procedures. Here, an “endoscope” is intended to include any scope that has a distal end configured to be inserted into a patient's body, and a proximal end configured to remain outside the patient's body during the procedure. Typically, the distal end comprises a viewport such as a lens or a window or a bare end of an optical fiber or even a mirror (such as a dentist mirror for example). Through the viewport, the scope enables collecting an image of the surrounding of the viewport, e.g. using a light-sensitive device such as a CCD. The viewport may be aimed to collect light from in front of the device (namely from a region coinciding with the longitudinal axis of the device), or the viewport may be slanted in an angle relative to the longitudinal axis, or may be facing perpendicular to the longitudinal axis of the device (as is demonstrated for example in colonoscopies). The proximal end typically includes or is connected to a handle to be held by a medical practitioner, possibly including user interface components such as switches, navigating sticks, touch screens and touch pads.
Endoscopes include a vast range of scopes, for example bronchoscopes, colonoscopes, cystoscopes and laparoscopes. A laparoscope—as a specific example—comprises a rigid or relatively rigid rod or shaft having a viewport, possibly including an objective lens, at the distal end, and an eyepiece and/or an integrated visual display at the proximal end. The scope may also be connected to a remote visual display device or a video camera to record surgical procedures.
In a laparoscopic procedure, the patient's abdominal or pelvic cavity is accessed through one or two or more relatively small incisions (typically between about 3 mm and about 15 mm) and a laparoscope may be inserted through one of the incisions to allow the practitioner a view of the internal organs to be operated on. The abdomen is typically inflated with a gas through the use of an insufflator—carbon dioxide is usually used for insufflation—to distend the abdominal space by elevating the abdominal wall above the internal organs and thereby create a sufficient working and viewing space for the surgeon.
The local environment within a patient's abdominal space is generally humid and warm compared to the laparoscope which is being inserted. Consequently, the viewport of the laparoscope tends to blur, e.g. due to fog, that is to say due to condensation of vapor on the viewport, or, for example, due to accumulation of droplets, e.g. blood droplets originating from surgical activity during the procedure.
Some existing techniques used to clean the viewport of endoscopes require retreating the endoscope from the patient's body, rinsing the viewport or wiping it (e.g. with a cloth) and possibly drying the distal end and worming it, to reduce and slow down blur formation after introducing the endoscope back in the patient's body. Other existing techniques include rinsing the viewport inside the patient's body. U.S. Pat. No. 8,047,215 discloses a laparoscopic lens cleaner which is suitable for maintaining the lens of a laparoscope in a clean, dry condition during a laparoscopic surgical procedure. An embodiment of the laparoscopic lens cleaner includes an elongated cleaner sheath having a sheath interior, a fluid conduit provided in the cleaner sheath, a fluid discharge nozzle provided in the sheath interior and communicating with the fluid conduit, a gas conduit provided in the cleaner sheath and a gas discharge nozzle provided in the sheath interior and communicating with the gas conduit. US patent application 20150005582 discloses a method of defogging and cleaning a laparoscope. The method includes: inserting a laparoscope into a sheath; inserting the laparoscope and sheath into a body cavity; providing gas to a plurality of gas lumens within a wall of the sheath such that the gas flows through the gas lumens and over a lens of the laparoscope to defog the lens while the laparoscope is in the body cavity; and providing a fluid comprising a surface-active agent to a fluid lumen within the wall of the sheath such that the fluid flows through the fluid lumen and over the lens to clean the lens while the laparoscope is in the body cavity.